|
Abstract
摘要 |
Optical settings with Parity-Time (PT) symmetry become one of the most widely studied platforms in probing the intriguing physics of non-Hermitian Hamiltonians. These include a variety of exotic phenomena associated with unique exceptional points and spontaneous PT phase transitions that are difficult to be observed in natural materials. In synthesizing such a compound system, gain and loss are usually placed in a balanced manner. In the first part of this talk, we will discuss our recent work on observing PT symmetry in two active-passive-coupled microtoroid cavities with high Q-factors. By balancing gain and loss, a cavity-guided “photonic molecules” could be formed in analogy with, say, Hydrogen atoms. In the second part of this talk, we will report the first experimental realization of anti-PT symmetry, a counterpart of PT symmetry, in a hot atomic vapor cell. Different from previous theoretical proposals and experimental demonstrations with solid materials, this work introduces a novel yet much simpler mechanism for implementing (anti-)PT symmetry without involving any advanced nanotechnologies or sophisticated nanofabrication techniques but is fully capable of unprecedented resolution to measure PT-phase transition. Of importance, this scheme firmly sets up a framework for probing non-Hermitian optics in the field of atomic, molecular and optical physics, where high controllability and excellent tunability offers competitive advantages over solid-material systems. Last but not the least, this scheme substantially reduces the complexity and cost on PT-symmetry implementations, and provides a very clean and simple platform that is reachable to most experimental groups. |
